It is often desired or necessary for medical reasons to close the fallopian tubes of a female for sterilization purposes. One method for sterilization of females is the placement of an implant or device within the fallopian tubes to occlude them. Total occlusion of the fallopian tubes prevents male sperm from fertilizing female eggs, thus preventing conception. Such implants are usually placed in the uterotubal junction, the narrowest part of the fallopian tubes.
The proper placement of implants in the fallopian tubes, however, has often proven to be difficult. If the implant is placed in the wrong location, it may cause serious medical problems for the patient or it may result in the fallopian tubes not being completely occluded and the patient not being sterilized.
A physician will usually perform a hysterosalpingogram (HSG) at about six to twelve weeks after the initial implant of the device to confirm the proper placement of the implant. An HSG involves pressurizing the uterus with radiopaque fluid while taking a real-time fluoroscopic image. The HSG test is a radiology procedure usually done in the radiology department of a hospital in which radiopaque fluid (dye) is injected into the uterine cavity through the vagina and cervix. The uterine cavity fills with dye and if the fallopian tubes are open, the dye will then fill the tubes and spill out into the abdominal cavity. In this way, it may be determined whether or not the fallopian tubes are open or occluded and where the occlusion is located.
One possible disadvantage of the HSG procedure is that the prior art implants are not seen in a fluoroscopic image because they are not radiopaque. In other words, the presence of the implant in the fallopian tubes is confirmed by the contrast of the radiopaque fluid and not actually by the implant itself. As a result, confirmation of the implant in the fallopian tubes and the associated occlusion of the fallopian tubes is at least in part a function of how well the test is performed. That is, the person performing the test must understand not only proper HSG technique, but also the general intended placement of the implant to ensure that the radiopaque fluid (dye) is indeed reaching the area of the implant.
Another possible disadvantage is that radiologists, not gynecologists, often perform the HSG. Although radiologists understand the HSG procedure, gynecologists may have a better understanding of the general intended placement of the implant in the fallopian tubes.
Therefore, there is a need for implants that are radiopaque and able to be easily detected in the fluoroscopic image during an HSG. This would make the detection of the implant easier for a radiologist or any physician performing the HSG after the implant has been placed in the fallopian tubes.
It is an object of the present invention to produce a radiopaque implant to be placed in the fallopian tubes. More specifically, it is another object of this invention to produce an implant that may be detected by a fluoroscopic image, e.g., during an HSG.
Another procedure for verifying proper placement of the implant is using ultrasound either transvaginally (TVUS) or transabdominally (TAUS). In either case, the ultrasound is operated using the Doppler mode to detect fluid velocity in the fallopian tubes, indicating a patent tube. In other modes, an ultrasound contrast agent is employed to image the presence of the distension media and contrast agent in the fallopian tube, which would indicate a patent tube. Typically, the ultrasound contrast media used in verifying the proper placement of the implant contains a suspension of gas bubbles of various sizes. One such ultrasound contrast method that makes use of these bubbles is called hysterosalpingo-contrast-sonography (HyCoSy). HyCoSy uses microbubbles in liquid to evaluate fallopian tube patency with ultrasound. An advantage of HyCoSy over HSG is that many gynecologists possess ultrasound equipment in their offices.
Therefore, it is an object of the present invention to produce an implant to be placed in the fallopian tubes that is both radiopaque and detectable using ultrasound. More specifically, it is another object of this invention to produce an implant that may be detected by a fluoroscopic image, e.g., during an HSG, and/or by ultrasound, e.g., using HyCoSy.